Regenerated RbR from deionized RbR (dIRbR) and fluorescent 3,6-diaminoacridine cation (DAA(+)) is studied as a function of the cation to dIRbR ratio. Using the fluorescence intensity of DAA(+), a Scatchard plot was drawn from which two DAA(+) are found to be strongly bound while more than three are found to be weakly bound. The retinal in reduced bacteriorhodopsin (RbR) is fluorescent. The fluorescence intensity and decay of the retinal are examined under conditions where there are two strongly bound DAA(+) per bR molecule. Assuming that energy transfer between the excited state of the retinal and the DAA(+) is responsible for the observed shortening of the retinal excited-state lifetime, the Forster model was used to estimate a donor-acceptor distance of less than or equal to 14 Angstrom. A discussion of the possible location of the DAA(+) with respect to the retinal is given. A comparison between the organic and metal cation binding is made, and a discussion of the possible location of the metal cations in bR is presented.